Tunneling magnetoresistance in Fe/MgO granular multilayers

García-García, A.; Vovk, A.; Pardo, J. A.; Sˇtrichovanec, P.; Algarabel, P. A.; Magén, C.; De Teresa, J. M.; Morellón, L.; Ibarra, M. R.
February 2010
Journal of Applied Physics;Feb2010, Vol. 107 Issue 3, p033704
Academic Journal
We have investigated the transport and magnetotransport properties in Fe/MgO multilayers around the Fe percolation threshold as a function of the temperature and the nominal thickness of iron layer (t). Electrical resistivity measurements allowed us to disclose the charge transport mechanisms involved, which are closely related to the degree of discontinuity in the Fe layers. The samples with Fe thickness below percolation threshold (t∼0.8 nm) exhibit isotropic magnetoresistance (MR), which can be understood considering spin-polarized electron tunneling between nanometer-sized, superparamagnetic Fe grains. The MR ratio increases with decreasing temperature from ∼3% at room temperature to ∼10% at 30 K. The temperature dependence of MR can be explained satisfactorily in terms of a modified Mitani’s model.


Related Articles

  • Tunnel magnetoresistance in GaMnAs: Going beyond Jullière formula. Brey, L.; Tejedor, C.; Fernóndez-Rossier, J. // Applied Physics Letters;9/13/2004, Vol. 85 Issue 11, p1996 

    The relation between tunnel magnetoresistance (TMR) and spin polarization is explored for GaMnAs/GaAlAs/GaMnAs structures where the carriers experience strong spin–orbit interactions. TMR is calculated using the Landauer approach. The materials are described in the 6 band k·p model...

  • Real-time evolution of tunneling magnetoresistance during annealing in CoFeB/MgO/CoFeB magnetic tunnel junctions. Wang, W. G.; Ni, C.; Rumaiz, A.; Wang, Y.; Fan, X.; Moriyama, T.; Cao, R.; Wen, Q. Y.; Zhang, H. W.; Xiao, John Q. // Applied Physics Letters;4/14/2008, Vol. 92 Issue 15, p152501 

    We report the study of the real-time evolution of tunneling magnetoresistance (TMR) in CoFeB/MgO/CoFeB junctions during annealing at 380 °C. The TMR quickly developed at the early stage of the annealing, with 200% magnetoresistance observed in less than 10 min, followed by a slow approach to...

  • Antiferromagnetically coupled CoFeB/Ru/CoFeB trilayers. Wiese, N.; Dimopoulos, T.; Rachrig, M.; Wecker, J.; Bráckl, H.; Reiss, G. // Applied Physics Letters;9/13/2004, Vol. 85 Issue 11, p2020 

    This work reports on the magnetic interlayer coupling between two amorphous CoFeB layers, separated by a thin Ru spacer. We observe an antiferromagnetic coupling which oscillates as a function of the Ru thickness x, with the second antiferromagnetic maximum found for x=1.0–1.1 nm. We have...

  • Evidence of s-wave subdominant order parameter in YBa2Cu3O7-δ from break-junction tunneling spectra. Akimenko, A. I.; Bobba, F.; Guibileo, F.; Gudimenko, V. A.; Piano, S.; Cucolo, A. M. // Low Temperature Physics;Feb2010, Vol. 36 Issue 2, p167 

    The tunneling spectra of YBa2Cu3O7-δ break junctions have been investigated for tunneling close to the node direction. The behavior of the zero-bias conductance peak (ZBCP) and the Josephson current have been studied as a function of the temperature and magnetic field. The deep splitting of...

  • Enhanced intergrain magnetoresistance in bulk Sr[sub 2]FeMoO[sub 6] through controlled processing. Sharma, A.; Berenov, A.; Rager, J.; Branford, W.; Bugoslavsky, Y.; Cohen, L. F.; MacManus-Driscoll, J. L. // Applied Physics Letters;9/22/2003, Vol. 83 Issue 12, p2384 

    Enhanced low field magnetoresistance (LFMR) values have been obtained in bulk Sr[sub 2]FeMoO[sub 6] through controlled processing. MR values, R(H)/R(0) of ∼60% [(R(H)-R(H=0)/R(H=0)=40%] were achieved at 50 K, in 1 T, and R(H)/R(0)∼8% [(R(H)-R(H=0)/R(H=0)=92%] at 290 K, in 1 T. For a...

  • Perpendicular spin torque promotes synchronization of magnetic tunnel junction based spin torque oscillators. Yan Zhou; Åkerman, Johan // Applied Physics Letters;3/16/2009, Vol. 94 Issue 11, p112503 

    We study how the perpendicular spin transfer torque term (bj), present in magnetic tunneling junctions (MTJs), affects the synchronization of serially connected MTJ-based spin torque oscillators (MTJ-STOs). We find that bj modifies the intrinsic preferred I-V phase shift in single MTJ-STO in...

  • Rashba spin-orbit effect on the zero conductance and the magnetoresistance of a quantum ring. Dong, Yan-Kun; Li, Yu-Xian // Journal of Applied Physics;Jun2008, Vol. 103 Issue 11, p113716 

    Using a mode matched scattering matrix method, we study the effect of Rashba spin-orbit coupling and a tunnel barrier on the zero conductance and the tunnel magnetoresistance (TMR) in a one-dimensional conducting Aharonov–Bohm ring symmetrically coupled to two ferromagnetic leads. It is...

  • Spin-polarized current and tunneling magnetoresistance in ferromagnetic gate bilayer graphene structures. Nguyen, V. Hung; Bournel, A.; Dollfus, P. // Journal of Applied Physics;Apr2011, Vol. 109 Issue 7, p073717 

    We study spin transport in bilayer graphene structures where gate electrodes are attached to ferromagnetic graphene. Due to the exchange field in the gated regions, the current becomes spin dependent and can be controlled by tuning the gate voltages. It is shown that thanks to strong resonant...

  • Modeling of bias anomaly in (Ga,Mn)As tunneling magnetoresistance structures. Sankowski, P.; Kacman, P.; Majewski, J. A. // Journal of Applied Physics;May2008, Vol. 103 Issue 10, p103709 

    We develop a simplified, Slonczewski-type model for the spin-dependent tunneling in (Ga,Mn)As-based trilayers to study the features that influence the bias anomaly, i.e., the drop in tunneling magnetoresistance (TMR) with the bias in these structures. By using the obtained closed formulas, we...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics